Abstract During the soybean protein production process, a large amount of wastewater is being produced. Currently in China, the soybean protein wastewater produced everyday has reached over 60,000 m3. A technology to bring about a better wastewater treatment effect with reasonable cost of the wastewater treatment is expected to be employed. In the present study, with a view to enhancing the discharge water quality, a combined processing method incorporating a pretreatment unit, an upflow anaerobic sludge blanket (UASB) reactor, an anoxic–oxic treatment system, and a biological aerated filter (BAF), was employed. After a steady performance of all the wastewater treatment units, the facilities will have the capacity to can handle 1,000 m3 wastewater with the chemical oxygen demand (COD) of 18,000 mg/L each day. The total COD removal efficiency can reach 99.84%, and the final discharge water will contain a COD of 40 mg/L. The wastewater treatment cost amounts to only about 2 Yuan RMB/m3 wastewater. Additiona...